The use of polyols in the preparation of polyurethanes by reaction of a polyol with a polyisocyanate in the presence of a catalyst and perhaps other ingredients is well known. Conventional polyols for polyurethane foams are usually made by the reaction of a polyhydric alcohol with an alkylene oxide to a molecular weight of about 2000 to about 3000 or more. These polyols are then reacted with polyisocyanate in the presence of water or other blowing agents such as the fluorocarbons to produce polyurethane foam.
Many different polyol initiators are known in the art. Polyol initiators which form linear or slightly branched polymers are molded to produce flexible urethane foams. Polyol initiators which form more highly branched polymers are used to produce rigid foams.
The alkoxylation in the preparation of any amino polyol is equilibrium limited. The method used to remove unreacted alkylene oxide in present industrial practice is to strip off residual alkylene oxide, leaving the alkoxylated amino polyol.
Kirk-Othmer, Encyclopedia of Chemical Technology, Second Edition, Vol. 16, page 598 and Stanford Research Institute, Report No. 45, Polyols from Ethylene Oxide and Propylene Oxide, both discuss generally the reaction of ammonia and amines with propylene oxide and ethylene oxide to form alkanol amines.
U.S. Pat. No. 3,297,597 (Edwards et al) describes the reaction of an alkylene oxide with the Mannich condensation product of a phenolic compound with formaldehyde and an alkanolamine.